The Rocky Horror Disco Show is credited to "David & Roxana", but there is just one male singer for the bulk of the track. Apparently Roxana sang only for the 'Touch-A, Touch-A, Touch Me' portions. The "Instrumental Version" is exactly the same as the "Vocal Version" except... no vocals (duh). Neither of these tracks were ever reissued on compact disc. One random amusement is that the first time through "Science Fiction/Double Feature", Flash Gordon apparently has purple underwear. Then at the end when they're reprising the song, he has yellow underwear instead. *shrug*